I've noticed that only if I preload the springs with the plastic rings (1.5 in the back + 1 big in the front) and I place them straight on the A-arms, there is more or less enough travel for the slash on landings, even if its a not big jumps or in other words, if I leave the shocks as is, the bottoming is too soft and the rear wheels scratch the hood upon landing or heavy accelerations / turns etc…
Anyway, I would like to give it more travel and make the slash a little more higher, any suggestion for long travel shocks, not a monster on but the kind that will add another 10mm of travel or so.
Maybe replacing only the springs to longer ones will add support and "push" the A-arms farther down.
Is the chassis bottoming out or are you just saying the wheels are being impacted up into the body? It is the latter just get a post kit to raise the body up a bit more.
I just read where one of the companys that builds bodies has developed a wheel well design that is wider and deeper to accomodate the wheel travel.
As the shocks are moved outward it increases the the resistance as it compresses and may be helpful in the hard landings for you.
You might even be able to stack some small O rings on the bottom of the shock shaft to act as snubbers as the reach full compression? Are you pretty sure you have the shocks filled properly and are using the correct wt oil for them for how you drive?
It looks like the shocks are simply too soft or maybe there should be a stiffer or longer spring in there, I have to use preload as it simply can't ride like that (stock springs and no preload).
I didn’t touch the shocks as I assume it's filled as it should with oil, we are talking about a brand new slash 2x4 out of the box - again, it's not that the shocks are completely useless, it's just the rear end that bottoms more then the front and IMO should have stiffer or longer sprig travel.
I can see that the A-arm is design for 2 shocks, maybe I'll add another pair of standard shocks for the rear-end ?
I'm not bashing it too hard as I'm still learning.
As it is now, if I start jumping hard, it will simply bottom all the way, there is no way that the shocks will do the job in the stock mode (IMO) meaning no preload etc.
your truck should ride level, drop it from 10inches or so and it should sit level and one spacer at a time to get there.
if you want more travel do what i did. get a set of rear shocks and a rear shock tower and put them on the front of your slash, use rear springs progressive -10 work good. the truck can can handle bigger jumps without bottoming out.
When you truck is air bound the suspension drops completely so springs don't matter there. Lowest you can be is best for cornering so going high is usually bad and causes constant rolling over. I would try thicker shock oil or even change the shock pistons if you haven't already to ones with less holes to restrict flow.
I have two of the thickest bump stop clips (two on each side) on the rear of my slash, and it has helped with the back bottoming out. I plan on getting stiffer springs for the rear since I'd rather not use so many pre load clips.
Don't assume that any shock is as it should be unless you inspect it. I have heard of several people using new shocks that were shipped void of oil thinking they had oil in them!
Only takes a few minutes, disconnect the shock at the bottom mount, remove the spring retainer and spring, push the plunger all the way in and see if it 'walks out' about 1/4-3/8in on its own, if it does you are normally OK on oil fill level, if not time to take it apart and properly fill it.
There is a normal amount of squat to the rear, just as if you were to begin jacking your car up the shocks have some squat in them and that is normal. The front arms will sit about level but the rears are a bit above level. Traxxas has the factory set up pretty soft in the back, a firmer spring can improve but don't over do it. As mentioned as you move the shock mounting point outward you will notice it becomes more progressive in resistance as the shock is compressed and this could help too. If you are most often landing big jumps you could also consider the 'one-hole' piston washers which will slow down the compression rate but then again may not follow the terrain as well on higher speed rough terrain runs.
Some good info here from Traxxas........http://traxxas.com/node/10068
Last edited by kwitty; 05-06-2012 at 12:05 AM.
This is when I just lay it gently on the surface (1 big preload spacer each shock).
This is when I drop it from about 15"
IMO it bottoms way too much, what do you think ?
Exactly, only if use 2 big spacer on each side it starts to look "ok" but of course that way you lose much of the spring travel itself.I have two of the thickest bump stop clips (two on each side) on the rear of my slash, and it has helped with the back bottoming out. I plan on getting stiffer springs for the rear since I'd rather not use so many pre load clips.
I've disconnect the shock from the bottom and squeezed the spring all the way (only the spring) and then pushed the plunger in all the way….but it doesn’t comes outdisconnect the shock at the bottom mount, remove the spring retainer and spring, push the plunger all the way in and see if it 'walks out' about 1/4-3/8in on its own, if it does you are normally OK on oil fill level, if not time to take it apart and properly fill it.
So, what is the next stage ?
The plunger alone without the spring should come back as I mentioned when you push it all the way in.
If not, remove the shock then the shock cap, it unscrews and fill it properly and you might select a heavier weight oil, many opinions on what weight. YouTube will show you nicely how to fill, there is a Proline video that nicely shows you how and you will see the plunger return a bit on its own when they are done. It may not solve all your tuning issues but when you have the foundation right the rest falls into place more effectively
The rear has way too much sag. When you drop it from a decent height, it should rebound to arms level, like in your first pic. Check to make sure nothing is binding in your suspension (hinge pins, shock pivots, etc.). If everything is moving freely, you either need to install more preload spacers until the arms sit level or get a heavier pair of springs.
Thank you both, I'm going to try heavier oil (what is suggested?) and check the tube vid for "how to"
From my long experience with off-road bike ride, I have a lot of experience with shocks and the basic idea is simple, the more preload spacer in = the more stiff the shocks are and the less travel / progression you get.The rear has way too much sag. When you drop it from a decent height, it should rebound to arms level, like in your first pic. Check to make sure nothing is binding in your suspension (hinge pins, shock pivots, etc.). If everything is moving freely, you either need to install more preload spacers until the arms sit level or get a heavier pair of springs.
Preload spacers are a "false solution" meaning the shock is stiffer but it has much less of travel, stiffer shock or heavier oil is the solution.
Spacers = Quick Fix
Heavier Oil = Slower rebound
Lighter Oil = Quicker rebound
Stronger, firmer Springs = Solution
As a basher, I use old things for instance I have a bunch of old tmaxx springs. For the front, I use the springs from the tmaxx (which are the same length as the rear shocks on the slash) and it gaves great travel and rebound. For the rear I have THREE spacers on each side. This make the rear spring right back up to its intial position which is what I prefer. There are other manufacturers of prings that will fit the Traxxas shocks and you may have to find them. Just search the forum for stiffer springs.
Rusty VXL W/ Sandrail Chassis (Coming soon...)
actualy im looking for stronger springs as well, there are many types, how do i read the rate / know how strong - resist it ?
Most people use the 2" losi springs on the front and the 2.5" losi springs on the rear. They have them color coded for each spring rate
What is equal (as a refernce point) to the stock springs that comes with the slash 2x4 VXL ?
To be honest nothing because the stock springs are linear. They are very soft at first and get firmer as they compress. On my race slash I'm running a losi red up front but its pretty soft as well. On the rear I'm actually running an old black traxxas spring which is between a losi orange and losi red rear spring
Sorry I meant the stock springs are progressive. Not linear. I tried tuning with the progressive springs and its almost impossible. A linear spring is really the way to go. The losi springs are linear and have a nice assortment to choose from
I was having the same issue. For what it's worth here's what I did....
Longer springs in back (were given to me, have no clue what they are)
Raised the body mount (this was the single best change to keep the wheels from rubbing the body)
Big bore shocks with 60wt oil rear /50wt front ( didn't really make it sit higher, but is much better on the large jumps on the track I run on)
Two large clips on rear shocks, one large in front.
Yes, this does make the vehicle *slightly* more top heavy, but it was a good tradeoff with it being much better on jumps. I have more dialing in to do, but that's the way I have it at the moment.
I was thinking actually about longer springs so I will not have to use the preloads.
I think I saw short springs that can be assembled together with the original ones as a kind of extension....
Have to look for that.
mudrunner, what was your solution? I ordered a set of Losi greens for the front, and blue for the rear.
My Black & Blue Rally is faster than your color...
simply installed a 1/8 shockes in the rear
Havent decided what to do with the front yet.
please give me your input regarding to your springs after you will test them, i might go for Losi front springs as well.